1. Field of the Invention
The present invention relates to an electrical connector, especially an electrical connector having a plurality of contact elements provided in a widthwise direction.
2. Description of the Related Art
Some electrical connectors applicable for a portable telephone are provided with a plurality of contact elements provided in a widthwise direction and capable of locking and unlocking the plugging with a mating connector only by inserting and removing the connector into and from the mating connector in a plugging direction. Since they do not need a button and so forth, they are called a simple lock type. This type of connector is mostly used for application requiring frequent plugging and removing operations. In order to perform smooth plugging operation, as shown in FIG. 12, guide projections 3 are provided on sides of contact elements of a connector 1 and a cavity 5 is provided in a metal case 4 of a mating connector 2 to receive the guide projection 3. For maintaining the plugging of the connectors 1 and 2 in a stable condition and keeping the contact between the contact elements of the connectors 1 and 2 in a good condition, a locking piece 6 made of a metal spring made by press is provided in the guide projection 3 and an engagement hole 7 made by press is provided in the metal case 4 to engage the locking piece 6.
When plugging the connector 1 into the mating connector 2, both the guide projections 3 are inserted into the cavity 6. The locking piece 6 is resiliently deformed (in downward direction in FIG. 12) to engage the engagement hole 7 so that the plugging condition between the connectors 1 and 2 is locked and the contact elements of the connectors 1 and 2 are brought into contact with each other.
When unplugging the connector 1 from the mating connector 2, the connector 1 is pulled (in a right direction in FIG. 12). The locking piece 6 is resiliently deformed again so that the engagement between the locking piece 6 and the engagement hole 7 is released and the plugging condition between the connectors 1 and 2 is also released.
Japanese Patent Application Kokai Number 11-16634 discloses a similar simple lock type connector.
However, in such a conventional connector, since the engagement between the locking piece 6 and the engagement hole 7 is performed only on one side, if the connector 1 is inserted into the mating connector 2 in an inclined condition, even if it is a small inclination in any direction, it is difficult to secure a good plugging between the connectors 1 and 2. Also, if forcibly inserted or removed, the connectors 1 and 2 may be broken, resulting in a malfunction.
Also, since the locking piece 6 and the engagement hole 7 are made by press, the fractures 8 and 9 of the locking piece 6 and the metal case 4 are brought into contact to each other every time the connector 1 and 2 plugged or unplugged. Consequently, the locking piece 6 and the metal case 4 are scraped away by friction of the contact, which gradually reduces the maintaining strength of the lock. Also, it is possible that shavings produced by the friction between the locking piece 6 and the metal case 7 are adhered to the contact element, which makes worse the contact condition between the connectors 1 and 2.
Moreover, since the locking piece 6 projects outwardly, it may be hooked on clothes during the plugging and unplugging operation of the connectors, which reduces the working efficiency.